A bit beautification of "Save unchanged" dialog.

* focus set to the list instead of the button
* list shows file icons
* replace hack that tried to avoid resizing save button by real fix
* Mac: left-aligned "do not save" button
* Mac: alternating colors in list
* Mac: same sized "cancel" and "save" buttons

Task-number: QTCREATORBUG-1120
Change-Id: Ic6aca8fca105517c3aaddc451640def43e955b77
Reviewed-by: Virva Auvinen <virva.auvinen@nokia.com>
Reviewed-by: David Schulz <david.schulz@nokia.com>

src/plugins/coreplugin/dialogs/saveitemsdialog.h

@@ -70,6 +70,8 @@ private slots:
     void updateSaveButton();
 
 private:
+    void adjustButtonWidths();
+
     Ui::SaveItemsDialog m_ui;
     QList<Core::IDocument*> m_itemsToSave;
 };